Comprehensive Kinetics on the C7H7 Potential Energy Surface under Combustion Conditions
Carles Martí1, Hope A Michelsen2, Habib N Najm1
1Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States.
The Journal of Physical Chemistry. A
|February 21, 2023
Summary
This study uses the KinBot code to map C7H7 chemical reactions relevant to soot formation in combustion. New pathways were discovered, improving our understanding of soot inception chemistry.
Area of Science:
- Chemical kinetics
- Combustion chemistry
- Reaction mechanism
Background:
- Soot inception is a critical process in combustion.
- Understanding the C7H7 potential energy surface is key to modeling soot formation.
- Existing models lack comprehensive characterization of relevant reaction pathways.
Purpose of the Study:
- To explore and characterize the C7H7 potential energy surface relevant to combustion.
- To identify and analyze reaction pathways involved in soot inception.
- To develop accurate rate coefficients for chemical modeling.
Main Methods:
- Utilized the automated kinetics workflow code, KinBot, for exploring reaction pathways.
- Investigated both low- and high-energy entry points for C7H7 reactions.
- Constructed a master equation using high-level theoretical calculations (CCSD(T)-F12a/cc-pVTZ//ωB97X-D/6-311++G(d,p)).
Main Results:
- Discovered three new reaction pathways, including a lower-energy route connecting benzyl with vinylcyclopentadienyl.
- Identified a benzyl decomposition mechanism leading to fulvenallene + H.
- Obtained rate coefficients that show excellent agreement with experimental measurements.
- Simulated concentration profiles and calculated branching fractions for key intermediates.
Conclusions:
- The KinBot code effectively maps complex potential energy surfaces for combustion chemistry.
- The identified pathways and calculated rate coefficients significantly advance the understanding of soot inception.
- This work provides a validated chemical model for simulating combustion environments and predicting soot formation.
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